John, Try Simple Green, it's a citrus based cleaner and foams so it lifts the dirt up and into the foam. it works wll on nicotine grunge as well.Also try using a wet/dry vac to suck up the stuff when it's wet, then wipe again with a clean rag. Don't use ammonia as it laeves a white stain/residue and buy a bunch of new cleaning rags, cotton, at a Auto Parts store or outlet. Swap cloths every 2-3 minutes as they get dirty fast and the greasy residue will be on the top surface, oil on top of water, so when it gets dirty you have to swap or risk putting the grase right back on the surface. For a textured surface use a soft nylon brush and circular action to lift the suff out of crevices. If you are claening the older vinyl headliner do no use a solvent based cleaner as it will dissolvve the foam backing on the headliner and it will rapidly decompose and sag. It also eats the glue that hold the liner to the roof trusses.